The present invention relates to an apparatus for preventing a fuel within a fuel tank for vehicle from flowing out of the fuel tank.
In a fuel tank for vehicle such as automobile, an evaporated fuel generated within the fuel tank is supplied to a canister where the evaporated fuel is absorbed. The evaporated fuel is supplied by the canister to the inlet system of an engine together with purge air. When the fuel is supplied into the vehicle, the evaporated fuel tends to flow out of the filler port of a filler tube, thereby contaminating the atmospheric air. To solve this problem, it has been recently proposed to communicate a vent tube for regulating the full level of the fuel to a canister which vents to the atmosphere and to seal the circumference of the inserted portion of a feed oil gun inserted into the filler port of the filler tube so that the fuel oil is fed into the fuel tank without any problems and the evaporated fuel is completely prevented from flowing out of the fuel tank via the filler tube.
In such a conventional vehicle, when the fuel oil is supplied into the fuel tank, the vent action by the vent tube is secured through the canister and the outflow of the evaporated fuel from the filling port of the filler tube is prevented. The evaporated fuel generated within the tank is fed to canisters through the vent tube and an evaporating tube separated from the vent tube. The evaporaed fuel is fed by the canisters to the inlet system of an engine together with a purge air.
When the fuel is supplied into the tank by the feed oil gun, the fuel level in the tank is regulated by blocking the end of the vent tube on fuel oil surface. The fuel is flowed into the vent tube by the difference between the fuel levels in the tank and the filler tube until the fuel level of the vent tube has reached the same level as the fuel level of the filler tube. The fuel in the vent tube tends to flow into its canister due to vibration of the vehicle etc. during its running so that the fuel cannot be sufficiently absorbed by the canister for the vent tube and may be leaked from the canister.